A circle has a sector with area $8\pi$ and central angle $\pi$ radian. What is the area of the circle? ${16\pi}$ $\color{#9D38BD}{\pi}$ ${8\pi}$
The ratio between the sector's central angle $\theta$ and $2 \pi$ radians is equal to the ratio between the sector's area, $A_s$ , and the whole circle's area, $A_c$ $\dfrac{\theta}{2 \pi} = \dfrac{A_s}{A_c}$ $\pi \div 2 \pi = 8\pi \div A_c$ $\dfrac{1}{2} = 8\pi \div A_c$ $A_c \times \dfrac{1}{2} = 8\pi$ $A_c = 8\pi \times 2$ $A_c = 16\pi$